[ASP.NET] 檔案讀寫權限問題

public ActionResult CNC()
        {
            //1.把EXCEL複製到本機
            if (!System.IO.Directory.Exists(@"D:\System Temp"))
            {
                // 目录不存在，建立目录
                System.IO.Directory.CreateDirectory(@"D:\System Temp");
            }

            //String sourcePath = Server.MapPath("~/Public/CNC機台狀態表.xlsx");
            string sourcePath = @"\\192.168.2.5\公共区\mis\Ren\Temp\CNC機台狀態表.xlsx";
            String targetPath = @"D:\System Temp\CNC機台狀態表.xlsx";
            bool isrewrite = true; // true=覆盖已存在的同名文件,false则反之
            System.IO.File.Copy(sourcePath, targetPath, isrewrite);
            //2.取得所有資料
            DataTable dt = new DataTable();
            string excelPath = targetPath;
            string strCon = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + excelPath + ";Extended Properties=‘Excel 12.0;HDR=YES;IMEX=1‘";
            OleDbConnection myConn = new OleDbConnection(strCon);
            string strCom = "SELECT count(*) FROM [機台總表$]";
            myConn.Open();
            OleDbDataAdapter myCommand = new OleDbDataAdapter(strCom, myConn);

            myCommand.Fill(dt);

            try
            {
                myCommand.Fill(dt);
            }
            catch (Exception)
            {
            }
            myConn.Close();
            ViewBag.Result = dt.Rows[0][0].ToString();
            ViewBag.Message = WindowsIdentity.GetCurrent().Name;
            return View();
        }

ViewBag.Message = WindowsIdentity.GetCurrent().Name;